Fabric arrangement and method for controlling fluid flow

ABSTRACT

In accordance with one aspect of the present invention, a material for an element of a power transmission-absorption assembly and the method of making such material is disclosed. The material has a pre-selected channel configuration to permit flow of a cooling medium thereacross or therethrough.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of Ser. No. 09/203,189 filed Nov. 30,1998 now issued as U.S. Pat. No. 5,998,311 which is a division of Ser.No. 08/794,178 filed Feb. 3, 1997 now issued as U.S. Pat. No. 5,842,551,which is a continuation of Ser. No. 08/316,204 filed Sep. 30, 1994 nowissued as U.S. Pat. No. 5,615,758.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fabric arrangement and method forcontrolling fluid flow and, more particularly, to a fabric arrangementand method for controlling fluid flow which may be utilized withfriction elements.

2. Description of Related Art

In clutches, brakes, automatic transmissions, limited slipdifferentials, hoists and similar friction power transmission and energyabsorption devices, there is generally provided one or more sets ofcooperating members, in which one of the cooperating members drives theother. It is not uncommon for these cooperating members to move in acooling medium or liquid, which is generally some type of lubricatingoil, and frequently the oil is force circulated about and between theengaging surfaces of the cooperating members so as to continuouslylubricate and cool them. In order to accomplish circulation of thecooling medium within blocker rings, clutch plates, transmission bandsand the like, the prior art has provided grooves or slots directly inthe engaging surfaces of one or both of the cooperating members or infriction material affixed thereto. For example, such a friction materialmay be a brass coating or a paper liner as seen in U.S. Pat. No.4,267,912 to Bauer et al., U.S. Pat. No. 4,878,282 to Bauer, and U.S.Pat. No. 4,260,047 to Nels.

Forming grooves within the friction material of cooperating members notonly adds complexity to the manufacture of such friction material andthe power transmission-absorption device, but also is limited in itsability to circulate cooling medium therethrough. In order to reduce oreliminate the hydrodynamic friction stemming from oil or cooling mediumlying on the surface of the friction material engaging the drivingmember, an improved friction material for circulating the cooling mediumis required, especially one which may be varied according to desiredparameters.

Prior art friction materials also include certain pyrolytic carbonfriction materials as seen in U.S. Pat. No. 4,700,823 to Winckler andU.S. Pat. No. 4,291,794 to Bauer. In such friction material, a meshedcloth substrate formed of carbon fibers is provided with a coating ofcarbon or other material being deposited on the fibers by chemical vapordeposition. This type of friction material has the characteristic of arelatively open mesh which allows ready penetration by an adhesive forimproved bonding, as well as a certain degree of porosity therethrough.However, as pointed out in the '794 patent, grooving of such material isstill provided in order to permit the flow of the cooling fluid betweenhe friction faces of the cooperating members of the power transmissionor energy absorption assembly. This type of friction material also doesnot easily provide highly bonded fibers at a friction surface of thematerial nor does it achieve a highly controlled texture as needed.Moreover, it has been found that such friction material is difficult tocompress to a desired thickness, such as during the process of bondingit to a member.

It is also seen that such pyrolytic friction material utilizes as itssubstrate a plain weave of the type illustrated in FIG. 6, where boththe fill and warp yarns of the material contact the cooperating element.Such an arrangement leads to increased wear of the friction material dueto the effect on the yarns oriented perpendicularly to the direction ofmotion for the cooperating element. Therefore, an additional desiredfeature not found in prior art devices is a friction surface texturewhich reduces wear on the friction material.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, a material isdisclosed having a plurality of first yarns and a plurality of secondyarns woven with the plurality of first yarns to form a predeterminedarrangement in order to control fluid flow.

A second aspect of the present invention is a friction power absorptionor power transmission assembly of the type having means for changing therelative position between a friction material and an opposing surfacematerial from a position of complete engagement to a position ofcomplete disengagement, the assembly including a first member, a secondopposing member, a friction facing material affixed to one of the firstand second members, the friction facing material being a woven fabrichaving a plurality of first yarns positioned in substantially parallelrelationship to each other and a plurality of second yarns woven inserpentine fashion over and under the first yarns to form a texturehaving a plurality of plateaus and valleys, wherein only the plateaus ofthe woven fabric engage the other of the members, and means forintroducing a liquid cooling medium between the first and secondmembers.

Further, a method of making a friction facing material for use in apower absorption-transmission assembly is disclosed involving the stepsof weaving a plurality of yarns in a predetermined pattern so as to forma woven fabric having a texture with a plurality of plateaus and valleystherein, fixing the woven fabric yarns in position, and providing anadhesive to the woven fabric.

Accordingly, one objective of the present invention is to provide afriction facing material for use with cooperating members of a powertransmission-absorption device which is able to circulate cooling mediumtherethrough without the need for machining additional grooves or slots.

A further objective of the present invention is to provide a frictionfacing material for use with cooperating members of a powertransmission-absorption device which can be oriented with respect to thedirection of movement between the cooperating members so as to reducewear and spin loss thereof.

Yet another objective of the present invention is to provide a frictionfacing material for use with cooperating members of a powertransmission-absorption device which can be woven so as to include flowchannels of desired size and orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the present invention, it is believed that thesame will be better understood from the following description taken inconjunction with the accompanying drawing in which:

FIG. 1 is a front view of a blocker ring having a friction facingmaterial bonded thereon in accordance with the present invention;

FIG. 2 is an enlarged, partial cross-sectional view of the blocker ringin FIG. 1;

FIG. 3 is an exploded perspective view of the blocker ring depicted inFIGS. 1 and 2 with its cooperating elements in a typical powertransmission-absorption assembly;

FIG. 4A, which is shown on the same sheet as FIG. 2, is an enlarged,diagrammatic side view of the friction facing material of FIGS. 1-3prior to bonding;

FIG. 4B, which is shown on the same sheet as FIG. 2, is a partial,magnified view of a single yarn in the friction facing material of FIG.4A;

FIG. 4C, which is shown on the same sheet as FIG. 2, is a partial,diagrammatic side view of the channels defined in the friction facingmaterial of FIG. 4A, where the plateaus and low points are depicted intheir state after bonding;

FIG. 5 is a plan view of the friction facing material depicted in FIG.4A;

FIG. 6 is a plan view of a prior art friction facing material having aplain weave;

FIG. 7 is a diagrammatic depiction of several exemplary weave styleswhich may be employed in the friction facing material of the presentinvention;

FIG. 8 is a diagrammatic depiction of the friction facing material ofthe present invention being circumferentially arranged asnon-interlocking arcuate segments on a clutch plate;

FIG. 9 is a diagrammatic depiction of the friction facing material ofthe present invention being circumferentially arranged as interlockingarcuate segments on a clutch plate;

FIG. 10 is a diagrammatic depiction of the friction facing material ofthe present invention being arranged as a plain cut full ring on aclutch plate;

FIG. 11 is a diagrammatic depiction of the friction facing material ofthe present invention being arranged as an edge wound full ring on aclutch plate;

FIG. 12A is a diagrammatic depiction of a strip of the friction facingmaterial of the present invention, where a plurality of notches havebeen formed therein;

FIG. 12B is a diagrammatic depiction of the strip of friction facingmaterial shown in FIG. 12A arranged on a clutch plate;

FIG. 13A is a diagrammatic depiction of a strip of friction facingmaterial of the present invention, where a plurality of lances have beenformed therein;

FIG. 13B is a diagrammatic depiction of the strip of friction facingmaterial shown in FIG. 13A arranged on a clutch plate;

FIG. 14 is a diagrammatic depiction of friction facing materials havingdifferent weave patterns, including some with several layers ofdifferent weave patterns, being circumferentially arranged asnon-interlocking arcuate segments on a clutch plate;

FIG. 15 depicts an enlarged, diagrammatic side view of an alternateembodiment for the friction facing material of the present invention;

FIG. 16 is an enlarged diagrammatic side view of a third embodiment ofthe friction facing material of the present invention; and

FIG. 17 is an enlarged diagrammatic side view of a fourth embodiment ofthe friction facing material of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawing in detail, wherein identical numeralsindicate the same elements throughout the figures, FIG. 1 depicts ablocker ring 10 including a friction facing material 15 affixed to aninner annular wall 12 thereof in conjunction with the present invention.It will be understood that blocker ring 10 is one element of a powertransmission or absorption assembly such as that utilized in clutches,brakes, automatic transmissions, limited slip differentials, hoists andother similar friction power transmission and energy absorption devices.One example of the environment in which blocker ring 10 may be utilizedis disclosed in U.S. Pat. No. 4,732,247 to Frost, which is herebyincorporated by reference. While blocker ring 10 and friction facingmaterial 15 discussed herein may be utilized with such friction powertransmission and energy absorption devices, it will be understood thatfriction facing material 15 of the present invention is not limited tosuch specific devices. For example, friction facing material 15 may beutilized in other friction devices such as clutch plates, torqueconverter clutches, and transmission bands. Moreover, it is contemplatedthat the material of the present invention could be utilized in otherdevices where the control of fluid flow is required, such as gaskets,filters, nozzles, and the like.

As seen in FIG. 1, blocker ring 10 includes three raised lugs 14 equallyspaced at 120° intervals around blocker ring 10. Lugs 14 may be nestedwithin associated hub notches of another member 17 of the assembly (notshown). As best seen in FIG. 3, blocker ring 10 also has a toothed orsplined surface 16 formed on the outer circumference thereof which isengagable with member 17 of the power transmission-absorption assemblyand thereby able to clock or rotate member 17 in accordance with acooperating friction element 18 causing movement along inner annularwall 12. As best seen in FIGS. 1 and 2, friction facing material 15 ofthe present invention is affixed to inner annular wall 12 of blockerring 10 by means of a layer of adhesive 20, such as nitrile phenolicadhesive. It will be understood that cooperating friction element 18(see FIG. 3) is movable along a longitudinal axis 19 in order to engageand disengage blocker ring 10.

FIG. 4A depicts a diagrammatic side view of friction facing material 15in its initial state, which includes a plurality of substantially linearfill yarns 25 arranged substantially parallel to each other. A pluralityof substantially parallel warp yarns 30 shown in a sinusoidal side viewin FIG. 4A are woven with fill yarns 25 in a serpentine fashion (i.e.,over and under adjacent fill yarns 25) to form a series of high points32 (known as “plateaus”) and a series of low points 34 (known as“adhesion points”). Positioned between each warp yarn 30 is a second setof warp yarns 31, which also are woven in serpentine fashion with fillyarns 25 to form a series of plateaus 33 and a series of adhesion points35. However, in order to maintain the construction of friction facingmaterial 15, warp yarns 31 are out of phase with warp yarns 30 so thatplateaus 32 of warp yarns 30 are opposite adhesion points 35 of warpyarns 31 and adhesion points 34 of warp yarns 30 are opposite plateaus33 of warp yarns 31. By weaving warp yarns 30 and 31 with fill yarns 25in this way, a plurality of upper channels 36 and 37 (known as“valleys”) are formed between adjacent plateaus 32 and adjacent plateaus33, respectively. Likewise, a plurality of lower channels 38 and 39 maybe formed between adjacent adhesion points 34 and adhesion points 35.

Further, as best seen in FIG. 5, fill yarns 25 may be tensioned by agreater amount than warp yarns 30 and 31, which also facilitatesdefining the formation of upper channels 36 and 37 in a predetermined ordesired weave pattern. Because plateaus 32 and 33 of warp yarns 30 and31 extend above fill yarns 25, it will be understood that only warp yarnsurfaces 30 a at plateaus 32 and warp yarn surfaces 31 a at plateaus 33(see FIG. 4A) of friction facing material 15 will engage cooperatingfriction member 18. In order to reduce wear of friction facing material15, it is preferred that warp yarns 30 and 31 be positioned so that theyare aligned substantially parallel to longitudinal axis 19 (see FIGS. 3and 4A) which is also the direction of relative motion between blockerring 10 and cooperating friction element 18 to reduce wear on frictionfacing material 15. It is to be noted that some prior art materialsprovide warp yarns and fill yarns having engaging surfaces at the samelevel (see FIG. 6). Consequently, at least some of the yarns areoriented substantially perpendicular to the direction of movementbetween the cooperating friction members. This, in turn, causesincreased wear of the material and/or the cooperating friction member.It should also be noted that while warp yarns 30 and 31 are shown asbeing woven with substantially linear fill yarns 25, the warp yarns maybe substantially linear and two sets of fill yarns may be woventherewith.

It will also be noted that a layer of adhesive 20 is preferably providedso that it engages only adhesive points 34 and 35 of warp yarns 30 and31, respectively. In this way, both upper channels 36 and 37 and lowerchannels 38 and 39 (see FIG. 4A) are able to provide flow paths forcooling medium, such as oil, in the power transmission-absorptionassembly.

As depicted by the side view representation in FIG. 4C, it will beunderstood that upper channels 36 and 37, as well as lower channels 38and 39, preferably have tapered sides 41 and 42. An angle Φ existsbetween side walls 41 and 42 and the respective plateaus and adhesionpoints of warp yarns 30 and 31, with angle Φ having an angle in therange of 20°-70°, and preferably approximately 45°. By having channels36-39 formed in this way, exiting of cooling medium therethrough isfacilitated due to the Bernoulli theorem.

Further, it will be seen from FIG. 4C that bonding of friction facingmaterial 15 onto a friction element will have a flattening effect onplateaus 32 and 33 of warp yarns 30 and 31, as well as on low points 34and 35 thereof.

Fill yarns 25 and warp yarns 30 and 31 preferably are carbonized bothbefore and after weaving, with friction facing material 15 preferablybeing saturated with resin and cured to further fix fill yarns 25 andwarp yarns 30 and 31 in the predetermined or desired weave pattern. Evenso, friction facing material 15 will generally retain interconnectionbetween upper channels 36 and upper channels 37, while maintainingdesired strength characteristics, provided the resin applied thereto ismaintained within a range of about 35-50% of friction facing material15.

With regard to the construction of fill yarns 25 and warp yarns 30 and31, it has been found that at least nine (9) twists per inch providesuitable definition of the texture for friction facing material 15. Inthis way, upper channels 36 and 37 and lower channels 38 and 39 thereofbecome more distinct, thereby increasing the ability of cooling mediumto flow therethrough. It will be understood that in order for fill yarns25 and warp yarns 30 and 31 to have nine twists per inch, an angle θexisting between each fibril 26 and a longitudinal axis 28 (see FIG.4B), is approximately 27° for a yarn having a diameter of 0.018 inches.Because there is a direct relationship between angle θ and the twistsper inch of the yarn, it will be understood that angle θ increases asthe twists per inch of the yarn increases. Thus, an angle θ of 27° orgreater for fibrils 26 of each yarn will consequently provide thedesired definition of the texture for friction facing material 15, aswell as a column strength that will desirably protect againstcompressive loads.

It will also be understood that during the yarn manufacturing, thefibrils 26 of warp yarns 30 and 31 will fracture at various points dueto the stretching thereof while in a carbonized state. Accordingly, suchfibrils 26 may have a length of approximately ¼ to 1 ½ inch betweenfracture points 27 (see FIG. 4C). This construction permits heat to beconducted through the length of a yarn by means of fibrils 26 tofracture points 27, whereupon the heat can then be transmitted to thecooling medium contained within lower channels 38 and 39.

Another preference of the embodiment herein described is to weave warpyarns 30 and 31 with fill yarns 25 so that plateaus 32 and 33 of warpyarns 30 and 31 have a maximum surface area across friction facingmaterial 15. One manner of increasing such surface area is to weave warpyarns 30 and 31 over more adjacent fill yarns 25 than the number ofadjacent fill yarns 25 they are woven under. For example, warp yarns 30and 31 may be woven over at least two adjacent fill yarns 25 and underat least one fewer adjacent fill yarns 25 alternatively to create asatin weave fabric (see, e.g., the crowfoot satin weave of FIG. 7, wherethe dark portions represent plateaus 32 and the white portions representvalleys 36 and 37 therebetween). This type of weave creates rectangularplateaus of increased surface area for contacting a cooperating frictionelement, which is particularly useful in a dry friction element such asbrake and clutch facings, whereby improvement in both wear resistanceand thermal conductivity is achieved.

It will be understood, however, that any number of weaves may beutilized or provided with friction facing material 15, including theexemplary weaves shown in FIG. 7 (e.g., plain, crowfoot satin, 2×2basket, 5 HS, 8 HS, Leno, {fraction (2/2)} twill, {fraction (2/1)}twill, non-crimp, ±45° plain, ±45° 8 HS, and ±45° crowfoot satin). Infact, such weaves may be selected, designed or utilized to control thesize, number, and orientation of upper channels 36 and 37 and lowerchannels 38 and 39, and consequently the flow paths across frictionfacing material 15. Accordingly, the amount and velocity of oil or othercooling medium forced across friction facing material 15 can becontrolled.

While a preferred material for friction facing material 15 is carbon, itwill be understood that fiberglass, silicone carbide, copper, ceramic,Kevlar, asbestos, or any other material having the required strength,temperature resistance, friction characteristics, and processibility forthe intended application may be utilized.

It will also be seen from FIGS. 15 and 16 that the friction facingmaterial of the present invention may have several layers of fill andwarp yarns. Such a multi-layered arrangement not only improves thedurability of friction facing material 15, but may include internalcooling vents which further enhances the flow of cooling oil or airtherein. Specifically, as seen in FIG. 15, friction facing material 115contains fill yarns in a dual layer—single layer—dual layer alternatingarrangement. A first set of warp yarns 45 is woven over dual layer fillyarns 47 a and 47 b and under single layer fill yarns 50 in serpentinefashion so as to form a plurality of high points or plateaus 52 and lowpoints 54. A second set of warp yarns 55, which is positioned betweenadjacent first warp yarns 45, is woven in serpentine fashion under duallayer fill yarns 47 a and 47 b and over single layer fill yarns 50(i.e., substantially 90° out of phase with first warp yarns 45) to formhigh points or plateaus 56 and low points or adhesion points 58 whichare opposite low points 54 and plateaus 52, respectively. A third set ofwarp yarns 60 is woven between dual layer fill yarns 47 a and 47 b andalternatively over and under single layer fill yarns 50, and ispreferably positioned between each adjacent first and second warp yarn45 and 55, respectively. Accordingly, a plurality of upper cooling vents65 and lower cooling vents 70 are formed within friction facing material115. Thus, not only are upper channels 46 between adjacent plateaus 52of first warp yarns 45 and lower channels 48 between adjacent adhesionpoints 58 of second warp yarns 55 present for flow of oil dischargethereacross, but internal cooling vents 65 and 70 may also be utilizedfor the flow of cooling oil or air.

Another embodiment of the friction facing material (designated by thenumber 215) is depicted in FIG. 16, where the multi-layered materialthereof may be provided or weaved to include internal cooling vents 75of predetermined size and shape. As seen therein, multiple layers ofsubstantially linear fill yarns 77 are arranged in a substantiallyparallel configuration. It will be seen that two sets of warp yarns 78and 80 are provided for each layer of fill yarns 77, where first warpyarns 78 and second warp yarns 80 are woven in serpentine fashion withfill yarns 77 but in juxtaposition with respect to each other so thatplateaus 82 and 84 and valleys 86 and 88 thereof are approximately 90°out of phase. In order to form a relatively large internal cooling orfluid flow vent or channel 75, certain specified fill strands (such as77A and 77B shown in phantom in FIG. 16) are omitted from variouslocations and layers to facilitate providing the cooling vent or channel75 having a predetermined configuration. Accordingly, first warp yarns78A, 78B and second warp yarns 80A, 80B normally woven with such omittedfill yarns 77A and 77B may be woven with fill yarns 77 of a differentlayer (e.g., top and bottom fill yarn layers L₁, and L₄ as shown in FIG.16). While warp yarns 78A, 78B, 80A, and 80B are shown as being wovenwith top and bottom layers L₁ and L₄ of fill yarns 77, thereby providingthe greatest available height dimension h for internal cooling vent 75,it will be understood that fill yarns 77 for any given layer may beomitted to provide internal cooling vents 75 of greater or lesser heighth so long as at least two layers of fill strands 77 remain for weavingpurposes. Further, any number of adjacent fill yarns 77 may be omittedto give internal cooling vent 75 a greater or lesser width. To simplifyweaving, it is preferred that internal cooling vents or channels 75 beof the same size and shape and repeat in symmetric fashion; however,internal cooling vents 75 may be dissimilar and asymmetric according tothe needs of a specific application.

Yet another alternative embodiment for the friction facing material ofthe present invention, identified by the numeral 315, is depicted inFIG. 17, where only a plurality of substantially parallel yarns(indicated as fill yarns 25 but also may be warp yarns) is provided inconjunction with a layer of scrim 21 on blocker ring 10. In thisarrangement, it is preferred that scrim 21 be saturated with adhesive orresin (although separate adhesive layers 20 a and 20 b may be utilized),whereby yarns 25 may be attached thereto and scrim 21 may be attached toinner annular wall 12 of blocker ring 10. It will be understood that aplurality of substantially linear channels 23 will be formed betweenadjacent fill yarns 25, which may be utilized to conductlubricating/cooling fluid across friction facing material 315. Dependingon a given application, it will be understood that channels 23 can beoriented on a friction element so as to be at an angle between 0° and90° to the sliding surface of the friction element.

While friction facing material 15 has been depicted as being positionedon inner annular wall 12 of blocker ring 10, it could just have easilybeen positioned upon an outer annular wall 22 of cooperating frictionelement 18 (see FIG. 3). Moreover, as seen in FIGS. 8-11, 12B, 13B, and14, friction facing material 15 may be utilized with other types offriction members such as a clutch plate 90, where it iscircumferentially positioned around a front or rear surface 92. Thereare several ways for friction facing material 15 to be positioned onclutch plate surface 92, such as non-interlocking arcuate segments 94(see FIG. 8). This arrangement forms channels 95 between each arcuatesegment 94 which may permit a greater flow of cooling oil than channels36 and 37, depending on the width of channels 95. Alternatively,friction facing material 15 may include interlocking arcuate segments 96to form a complete ring around clutch plate surface 92, as seen in FIG.9 and disclosed in U.S. Pat. No. 4,260,047 to Nels which is herebyincorporated by reference. As seen therein, each interlocking segment 96includes a male extension 98 at a first end and a female receptacle 99at a second end which may be mated together. The advantages of utilizingarcuate segments 94 or 96 for a ring-shaped object like clutch platesurface 92 are that it saves material during the blanking process andallows the yarn cooperating with the mating surface to remainapproximately parallel with the direction of engagement anddisengagement between the friction elements. Nevertheless, frictionfacing material 15 may be plain cut (or blanked) as a full ring 100 (seeFIG. 10).

Alternatively, a strip of friction facing material 15 may be formed intoa flattened hoop 102 so that it may be edge wound about clutch platesurface 92 as seen in FIG. 11. Such a strip of friction facing material15 preferably includes a single male extension 104 at one end and asingle female receptacle 105 at the other end so that each end of hoop102 may be properly mated.

As seen in FIGS. 12A and 13A, strips 106 and 107 of friction facingmaterial 15 may have notches 108 or lances 109 formed therein. Then,strips 106 and 107 may be positioned on clutch plate surface 92 as seenin FIGS. 12B and 13B, whereby notches 108 are brought together or lances109 are pulled apart. In either case, strips 106 and 107 form amulti-sided shape that is sized to fit on clutch plate surface 92.

As shown in FIG. 14, it will be understood that friction facing materialof different weaves may be utilized together. There, friction facingmaterial 110, 111, and 112 of various weaves are attached to surface 92of clutch plate 90 in the form of non-interlocking arcuate segments. Itwill be seen that friction facing material 110 has the greatest numberof flow paths as defined by upper channels 36 and 37 (indicated by whiteareas 116), thereby permitting the greatest amount of cooling flow.Friction facing material 111 has some flow paths, but fewer thanfriction facing material 110. Finally, friction facing material 112 hasno leakage paths. Thus, depending on the desired amount of coolingmedium flow or leakage for a particular area, the friction facingmaterial can be tailored thereto. This may be taken a step further,wherein friction facing material 110, 111, and 112 of different weavesmay be radially aligned in several layers as shown in FIG. 14. In thisway, complete control of the flow characteristics for a givenapplication may be controlled solely by the weave and arrangement of thefriction facing material.

With respect to the method of making friction facing material 15, itwill be understood that fill yarns 25 and warp yarns 30 and 31preferably are initially carbonized in a high temperature oven.Thereafter, fill yarns 25 and warp yarns 30 and 31 are woven in adesignated pattern for the particular application so that channels 36,37, 38 and 39, and possibly cooling vents 65, 70 or 75, are formed toprovide the requisite flow paths. In order to fix or lock the wovenpattern of fill yarns 25 and warp yarns 30 and 31, friction facingmaterial 15 is then preferably carbonized again in a high temperatureoven. To further enhance the locking process, friction facing material15 preferably is saturated with a resin, such as a phenolic resin, andcured at an appropriate amount initially in an oven and subsequently atan appropriate amount during the bonding process described hereinafter.

Once the above steps have been accomplished, adhesive 20 is then appliedto one surface of the saturated fabric, such as by lamination. Frictionfacing material 15 is then ready for blanking, where either arcuatesegments, whole rings, or strips are cut from the rolls of material.Lastly, friction facing material 15 is bonded to a desired frictionelement, such as blocker ring 10 or clutch plate 90. It has been foundthat a punch-die arrangement works well to press friction facingmaterial 15 into place on blocker ring 10. For example, the punch mayprovide pressure in the range of 50-800 lbs. per square inch forapproximately 40-100 seconds. In order to prevent adhesive 20 andphenolic resin from wicking into friction facing material 15 during thisprocess, since adhesive 20 will tend to be attracted to the elementhaving a higher temperature, a temperature differential preferably isestablished between the punch and the die (e.g., the die preferablyhaving a temperature of approximately 550° F. and the punch having aninitial temperature of approximately 250° F. increasing to approximately400° F. during the bond cycle as heat moves from the die through thering adhesive layer, and friction facing material into the punch).

Having shown and described the preferred embodiments of the presentinvention, wherein an inventive friction facing material, the method ofmaking the friction facing material, and a friction element includingthe friction facing material thereon have been disclosed, it will beunderstood that further adaptations thereof may be accomplished byappropriate modifications by one of ordinary skill in the art withoutdeparting from the scope of the invention. In particular, while theembodiments of the inventive friction facing material have beendescribed herein as preferably including warp yarns weaving with aplurality of substantially linear fill yarns, the opposite thereof isalso contemplated (i.e., where fill yarns may be woven with a pluralityof substantially linear warp yarns). Further, the specific weaves andmaterials disclosed herein are also preferred embodiments, since theyarns may also be braided, but should not be deemed limiting on theintent of the present invention.

It should also be appreciated that the invention could be applied to awet or dry environment where the control of fluid flow is required, andthe channels defined by the predetermined yarn arrangement may be usedto channel heating or cooling fluids, including gases and liquids.

What is claimed is:
 1. A friction element comprising: a friction member;a plurality of warp yarns; a plurality of fill yarns; said plurality ofwarp yarns and said plurality of fill yarns being woven to define awoven pattern for facilitating transferring heat away from said frictionmember; and an adhesive for adhering said woven pattern to said frictionmember.
 2. The friction element as recited in claim 1 wherein said wovenpattern defines a plurality of channels on a surface of said frictionelement when said woven material is placed on said friction element. 3.The friction element as recited in claim 1 wherein said woven patterndefines a plurality of channels interior to said woven material.